Generally, a polymer is a larger molecule comprised of multiple repeated smaller molecules known as monomers. During a process known as polymerization, the monomers may be covalently bonded to each other forming larger polymer chains. The composition and arrangement of the monomers may determine the characteristics of the polymer, for example, determining the biodegradability and biobased content of the polymer.
The biobased content of the polymer relates to the raw material sources from which the monomers are derived. Specifically, the degree of biobased content depends on the amount of carbons in the monomers which are derived from biological, recycled, renewable, or otherwise sustainable materials. Such biological materials may include sources such as crop residues, wood residues, grasses, municipal solid waste, and algae. A polymer with higher biobased content may be preferable for use in sustainable and environmentally responsible applications.
Biodegradable polymers may also be beneficial in environmentally responsible applications. Biodegradable polymers generally include a main chain comprised of bonded organic molecules which may decompose by natural processes into smaller environmentally compatible molecules. The specific chemical composition of the monomers in the biodegradable polymers will determine what smaller molecules are produced by decomposition, the mechanisms by which decomposition occurs, and the rate at which decomposition occurs.
Many conventional polymers may not be comprised of monomers which confer characteristics of biodegradability or some degree of biobased content. In addition, modifying conventional processes to produce environmentally responsible polymers may be costly, require long production cycles, and/or be difficult to modify.
Generally, sanitary articles such as disposable diapers, adult incontinence pads, feminine hygiene products, and sanitary napkins include an absorbent core to receive and retain liquids. For absorbent articles to function efficiently, the absorbent core must quickly acquire liquids into the structure, preferably wicking the liquids away from the body of the wearer with a specialized topsheet layer. The liquids may easily penetrate the topsheet and be absorbed by the absorbent core. The retained fluids may also not penetrate a hydrophobic backsheet which is positioned farthest from a wearer's body.
The topsheet is generally compliant, soft feeling, and non-irritating to the wearer's skin while maintaining a liquid pervious characteristic, permitting liquids to readily penetrate through its thickness. A conventional topsheet may be manufactured from a wide range of materials, such as porous foams, reticulated foams, apertured plastic films, natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polyester or polypropylene fibers) or from a combination of natural and/or synthetic fibers. Conventionally, the topsheet is made of a material intended to isolate the wearer's skin from liquids contained in the absorbent core.
The backsheet is generally impervious to liquids and is conventionally manufactured from a thin plastic film, such as polypropylene or polyethylene, although other materials may also be used. The backsheet prevents the fluids which are absorbed and contained in the absorbent core from soiling articles of clothing which contact the sanitary article such as bedsheets and undergarments. Similar to the topsheet, the back sheet is generally flexible and compliant to readily conform to the general shape and contours of the wearer's body.
The absorbent core is generally positioned between the topsheet and the backsheet to form the sanitary article. The absorbent core is generally compressible, conformable, non-irritating to the wearer's skin, and capable of absorbing and retaining liquids and certain body excretions. The absorbent core may conventionally comprise laminates or combinations of several sheets or webs of the requisite type of materials.
There exists a need for improved biodegradability of sanitary articles. The present invention solves this need by providing for sanitary articles comprised of polymeric material having increased biodegradability and biobased content.